OK so I have been running some more tests. It seems to only be happening to a a few accounts. So far the pattern is Android devices with Vodacom contracts (mobileGenericPlan,Vodacom,mobilePushEnabledPlan) or something along those lines. Like I said before I only get it when I use my native browser.In fact in my testing so far it is limited to Galaxy s2 handsets.

are you sure you don't have some sort of autofill feature which could be propagated from your phone settings or even online via a google/facebook account?

Have you tried clearing all history, cookies and browser autofill history?

Definitely passed thorough the headers. That is how I am extracting it with php, I am asking for the header information. For some reason it does not do it when I use Firefox. So that is my quick fix solution for now.

From what I can ascertain the information is passed in the headers,not a form(submit) block

Definitely passed in the headers. Checked with a Samsung GS2, but what's weird is it seems to be only passed by the native browser when the VC proxy is used. Turn off the proxy, headers gone. Also checked with Dolphin browser and no such headers are set with or without VC proxy.

Tethered via usb, checked with pc and no headers.

So must be the combo of native browser and VC proxy...

"It is difficult to get a man to understand something when his salary depends upon his not understanding it." - Upton Sinclair

Yes this is what I have found with my testing so far. This is not exclusively a Android thing though as I have tested an older Nokia symbian that did it, a blackberry torch and a HTC Desire (although this is also android). I'm just not sure if Vodacom is putting the headers in but some software (OS or Browsers or whatever) is stripping it, or if Vodacom is supposed to be stripping this information and is struggling in some cases to do so. I think its the former though.

The older sims, when you got the package with the sim, the cell number was printed on the packaging. With the new packs, the number is only assigned to the sim after it is activated.

Now what i was thinking, maybe on the older sim cards the actual cell number was "programmed" into the sim, hence why the phone - and browser - could retrieve the number and thus send it as a header. The newer sims don't have this, and thus the device cannot set these headers.